Which has served you more, Lean or Six-Sigma?

My systems post grad, experience, and military viewpoint is sure to torque the Brass off. LSS had merit as it pushed the process people to focus on minimum inputs, hence eliminate waste in all forms. Then it was pushed outside the valid process limits it was designed for and used for things it wasn't designed for. Then it got weaponized internally and then politicized. Having been in from 'Nam to Sandbox, the services institutionalized the Whiz Kids mentality into an onerous system that removed the trigger puller further away from anyone that might care. Then the topic infiltrated promotion boards (sat many early '2000s) and almost set up a two class system of have and have nots. The general drift is people started using LSS and other process notions as a substitute for leadership, and the rest is history. Not like I have formed an opinion over 42 years dealing with the thing of the moment. Pro tip: "A Man's got to know his limitations." Dirty Harry.

My thought is if the training will benefit you extrinsically by improving your marketability, go for it. As for me, LSS offers zero value in my current military and upcoming civilian career path. Best of luck to you!

I have pulled a lot of both. Most of the tools you get are incorporated into everything you do unconsciously as a matter of efficiency improvement.